Direct communication between user equipment and generated services are referred to as device to device proximity services (D2D ProSe), have become a research subject in a system of the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Re1.12, and are supported starting from the Re1.12 system. The direct communication between user equipments includes a discovery signal process and a direct communication process. The discovery signal process includes sending a discovery signal and receiving the discovery signal. The direct communication process includes a series of processes of call initiation, channel measurement, channel feedback, resource scheduling, data transmission, call completion, and the like.
After one user equipment requests a network device to allow the user equipment to perform direct communication with another user equipment, the network device sends a paging message to the other user equipment in multiple cells within a range of a tracking area list of the another user equipment, for paging the user equipment. When a location of the user equipment in a cell included in the tracking area list changes and a cell is reselected, an update of the tracking area list is not triggered. An update procedure of the tracking area list is triggered only when a new cell to which the user equipment is handed over does not belong to the tracking area list. Therefore, the network device cannot determine which cell, in the tracking area list, in which the user equipment is currently located. The network device initiates paging in multiple cells in the tracking area list, which causes an unnecessary waste of resources.